The Alesis Ion and Micron (and Akai Miniak) all use the same Alesis-designed AL3101 DSP chip, one per voice. (See for instance MATRIXSYNTH: Inside the Alesis Micron). The Coldfire seems to be used as a control processor.
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Oh, very interesting. It did seem incredible that they got all that sound from what was basically a souped up 68000! Although it does have some sort of DSP enhancement(s), like a ‘Multiply and Add’ instruction. I wonder if it even used any of them. Thanks for the pointer.
The RPi5 does not have 3.5mm audio jack so we would lose the ability to build a Zynthian with no extra hardware. This is something that we suggest to nervous investors… those who want to see how wonderful Zynthian is without the commitment. It’s also the output we planned to use for accessibility enhancement so we would need to rethink some of this.
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True, but I think we, as in royal ‘we’, might be able to substitute the ability to route output via Bluetooth to a speaker or earbuds. I think most people have some kind of ability to listen via a Bluetooth device.
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Amazing. I find very fascinating the concept of emulating a slower purpose-built processor within the instructions of a faster general-purpose CPU.
There must have been quite a lot of reverse-engineering in devising/guessing which specific ROM-level signal processing routines have been used by Access, in their specific implementation of the DSP kernel macros available for the chosen Motorola processor.
The programming aesthetics in reproducing DSP nuclei as adaptive real-time bits of code and related CPU processes is very elegant. 
It’s easy enough to plug in a USB sound card for a tryout as well though. I think as long as you keep compatibility with generic USB devices, it’ll end up being a better experience for tire kickers, cause as we all know, that jack was not good sound.
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We do lose the audio jack in this revision. Not end of the world, but it has been useful for headphones + line out.
Am I wrong or was the buildin audio jack 12bit PWM only? Hmmm…, sorry, but IMHO this is only useful for testing.
Exactly. It also works “good enough” as a headphone monitor I guess.
The original implementation of the onboard sound was truly terrible. There was an improvement a few years ago which made it not too bad. It certainly isn’t audiophile quality but it is a really useful output for beginners and toe-tippers to use. It allows someone to build a Zynthian without any external hardware which is a great option for testing whether this is something worth investing in. These people may not have a USB soundcard lying around.
We also use the onboard sound as the headphone feed on older models and some users may wish to continue to do so.
We have also been working on accessibility options that output audio description via this output to be mixed with the main output to a headphone feed.
So this will be a loss but we can find ways to work around most of that.
Note that using the onboard sound is a bad idea generally, not just because of its limited audio quality but also because it is bit-banged and consumes quite a bit of CPU which can lead to xruns. (This is why I don’t like using it as a headphone output where the problem is compounded by the need to samplerate convert to sync the audio clocks.)
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The new RP1 chipset is the more exciting piece in this RBPi5 imo.
The Gpios header pins aren’t directly connected To CPU anymore but are now "programmable " through RP1 chipset.
So I wonder if more I2S data lanes are possible ?
Looking forward to the zynthian 255 channel mixing desk synth in that case!
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No:
255+0=256=2⁸
this is too much for me. I’m not like Berlioz, which has involved a double symphonic orchestra or a triple choir in his compositions (with eventually, the famous octobass).
No. But having a different mix for the headphones and for the main output is for me a must have in my use case of the Zyn
I understand your use-case, but, sorry, this is not something we are going to implement any time soon. First, this requires separate channels for headphones and main output, what is difficult with current I2S hardware. Second, we should modify the software:
- at core level, what effectively duplicates the CPU resources used by the mixer
- at a UI level too, modifying the workflow accordingly
Also, there are interesting questions, like:
- If we have different mixes for main and headphones, then, should we have separated “Main FX” and “Headphones FX” chains?
- Should be duplicated chains or could it be interesting to have fully independent FX chains for Main and Headphones?
- If they are duplicated FX chains, things are very “funny”. Because every processor is duplicated, when you change a control parameter in the GUI, the parameter must be changed in 2 processors. Same for MIDI learning, etc.
So, don’t expect this to be implemented in the next weeks/months 
The best,
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hi @jofemodo,
I would like to ask a similar thing. It goes a bit outside the official Zynthian. It would be possible to route the second output for USB sound cards. I will take, for example, the popular behringer umc404hd. Something like:
Channel 1 -> Main output -> Umc404hd out 1
-> Umc404hd out 2
Channel 2 -> Main output -> Umc404hd out 1
-> Umc404hd out 2
-> Second output -> Umc404hd out 3
-> Umc404hd out 4
Channel 3 -> Second output -> Umc404hd out 3
-> Umc404hd out 4
Something similar to how the audio input is organized now, where it is possible to choose the input number from the sound card.
Hi @jofemodo thank you for your feedback.
yeah, that’s why I’m asking myself
with RP1 chipset. Having a look at RP1 current documentation (on page 51/93) it seems to be the case.
Yes, I totally agree and I have to admit that brainstorming on how to present this feature in the UI hasn’t produced any concrete concept yet
Cheers
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Although the RP1 has several I2C channels I am not sure whether they will be exposed on the RPi which will probably maintains 40-pin header compatibility.
I would like to be able to offer routing to different outputs. I think we used to do this (but I could be confused) and that seems like a useful feature. It may then offer the ability to construct mix groups but as @jofemodo points out, each mix bus requires processing. We can look at what’s possible in the future.
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Since the Pi4 & 5 both have four hardware serial ports, would it be possible to make Zynthian a MIDI merger/router for multiple devices?
Hi @jofemodo, can you roughly estimate a time when the aluminum cooling block for the PI5 in combination with Zynthian V5 would be available in your Shop?
Or is this a larger HW change?
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